Means for preventing escape of unfused ore from smelting-converters.



PATENTED AUG. 27, 1907.

R. BA GGALEY, C. M. ALLEN 6; B. W. LINDQUIST.

MEANS POR'PREVENTING ESCAPE 0F UNFUSBD ORE FROM SMELTING con-vna'rsas.

APPLICATION FILED MAY'I. 1905.

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'No.864,719. PATENTED AUG.27, 1907. R. BAGGALEY, 0. M. ALLEN & E. w.LINDQUIST. MEANS FOR PREVENTING ESCAPE 0P UNFUSBD ORE PROM SMBLTINGCONVERTERS.

APPLICATION FILED MAY 1, 1905.

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No. 864,719. EATENTEE AUG. 27, 1907. R. BAGGALEY, o. M. ALLEN & E. w.LINDQUIST. MEANS FOR PREVENTING ESCAPE 0E UNPUSED ORE FROM SMELTINGCONVERTERS.

APPLICATION FILED MAY 1. 1905. 4 SHEJE ml NORRIS Psi-nu: cm, wunmaron:ax.

No. 864,719. PATENTED AUG. 27, 1907.

R. BAGGALEY, G. M. ALLEN & E. W. LINDQUIST. MEANS FOR PREVENTING ESCAP EOF UNPUSED ORE FROM SMELTING CONVERTERS. I

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UNITED STATES RALPH BAGGALEY, OF PITTSBURG, PENNSYLVANIA, CHARLES M.ALLEN, OF LO LO, MONTANA, AND EDWARD W. LINDQUIST, OF CHICAGO, ILLINOIS;SAID ALLEN AND SAID LINDQUIST ASSIGNORS TO SAID BAGGALEY.

MEANS FOR PREVENTING ESCAPE OF UNFUSED ORE FROM SMELTING-CONVERTERS.

Specification of Letters Patent.

Patented Aug. 27, 1907.

Application filed my 1,1905. Serial No. 258,426.

To all whom it may concern:

Be it known that we, RALPH BAGGALEY, of Pittsburg, Allegheny county,Pennsylvania, CHARLES M. ALLEN, of Lo Lo, Missoula county, Montana, andEDWARD W. LINDQUIST, of Chicago, Cook county, Illinois, have in vented anew and useful Means for Preventing Escape of Unfused Ore fromSmeltinglonverters, of which the following is a lull, clear, and exactdescription, reference being had to the accompanying drawings, formingpart oi this specification, in which Figure 1 shows in cross-section, asmelting converter provided with our preferred form of apparatus, thesection being on the line II of Fig. 2; Fig. 2 shows in verticallongitudinal section on the line III I of Fig. 1, a smelting converterequipped with our preferred form of apparatus. It also illustrates theremovable block whereby the bridge may be removed from the converter, ifdesired. Fig. 3 illustrates a partial side elevation of a smeltingconverter equipped with our preferred form of apparatus; Fig. 4;illustrates in crosssection, a smelting converter equipped with analternate form of our apparatus; Fig. 5 is a longitudinal cross-sectionpartly broken away on the line V-V of Fig. 4; and Fig. 6 illustrates inlongitudinal section, the discharge end of a smelting converter,together with the water-jacketed overflowspout, the practicallyair-tight drop-tube and a portion of the forehearth, the design of thedischarge orifice being such as to prevent the exit of unfused floatingore without trapping the blast.

Our invention is especially designed for use in connection with themethod and the apparatus more fully described in other applicationsfiled by us, to wit: Serial No. 243,677, filed February 1, 1905, methodof smelting ores and separating mattes, and Serial No.

253,548, filed April 3rd, 1905, smelting converter and forehearth. Itsobject is to prevent the escape from the converter, of lumps orparticles of ore in an unfused condition.

The smelting converter described in the cases referred to is preferablysix feet in diameter and twenty feet in length. Its area is equivalentto the cross-sectional area of an ordinary copper blast furnace largeenough to smelt six hundred tons of ore in twenty-four hours. The blastprovided in this vessel is ample to smelt the tonnage referred to. Forevery one hundred pounds of ore fed into this smelting converter, onehundred pounds of molten material, either matte or slag, less thevolatile portion such as that portion of the sulfur which is oxidized toS0 must be discharged through the overflow-spout, in a correspondingspace of time.

If the vessel be therefore smelting ore at the rate of 600 tons in 24hours, it will reduce to the molten state 25 tons of ore per hour ormore than 800 pounds per minute. This explanation will make the factclear that the move ment of slag and matte from the vessel into theforehearth will be extremely rapid.

In regular blast furnace smelting with a trapped overflow-spout and witha column of ore, flux and fuel, as used on the lines of universalpractice, we have found that the column of charge so obstructs the blastescape through it, as to cause considerable air-pressure on the top ofthe molten material which is constantly in the crucible of the furnace,intimately mingled with the material of the charge. This pressure issufiicient to force down the top surface of the molten slag a distancewithin the crucible of the furnace of from one and one-half to twoinches. Such top pressure seems to have the effect of expelling themolten matte from the crucible of the furnace, and the top layer ofmolten slag seems to constantly increase In this way a floating layer ofmolten slag may accumulate to a depth of from eight to twelve inches,and anyone conversant with converter practice and especially with thedissolving of ores on a molten bath will be familiar with the troublesthat would be experienced if this accumulation were allowed to occur. Itis because of these things that we are careful to avoid the trapping ofany blast in the smelting converter above referred to; because thiswould cause a top layer of molten slag 011 which unfused ore would floathopelessly separated from the molten matte that alone could dissolve theore. This separation of the unfused ore from the body of molten mattewould be fatal to the successful practice of this new method ofsmelting. It is also known to those conversant with the converting ofmattes, that the rotary motion given to the charge by the entering blastcauses the slag to be mixed more or less with the matte.

If the relative proportion of slag t0 matte be small enough, no seriousresults will fullow; but when the slag increases beyond a certainamount, then it chills at the twyers and forms noses and thus createsdifficulties which, if the cause be not speedily removed, will result ina stoppage of the entire operation. It is of paramount importance thatthe slag should be freely and quickly and thoroughly discharged throughthe overflow, in order that the entering, uniused ore may always comeinto immediate contact with and thereafter float in a comparativelyclean bath of molten matte, towards the overflow-spout, approximately adistance of twenty feet, while subjected to the heat produced by theconverting blast. If this overflow-spout be trapped against the escapeof the blast, a top layer of slag will quickly accumulate and it willexert a certain amount of downward pressure on the molten matte becauseof the choked escape of the enormous volumes of gas at all times burningin the upper portion of the vessel, and which continuously producesmelting temperatures in its upper portion above the level of the moltenbath. the top layer of molten slag will force the escape through theoverflow-spout of an undue proportion of the molten matte, exactly as itnow does from the crucible of the common copper blast furnace, and whilethis is a desirable condition in the blast furnace it is just thereverse in an ore-dissolving converter.

In the apparatus illustrated in the cases above referred to, the levelof the top layer of molten bath can never exceed that of the centralline of the overflowspout as shown in Fig. 2. For this reason the upperhalf of the overflow-spout is constantly open, so that no trapping ofthe blast can possibly occur.

From the thirty-two 1; inch converting twyers on the side of the vessel,an enormous volume of converting blast constantly enters. The thin layerof floating slag that is constantly .forming through the action of theintense heat may be silicious, and for this reason it may be more orless pasty. The entrance of this enormous volume of blast, throughoutthe entire length of the vessel, will have a constant aerating orlightening effect on the molten material and particularly on the thinlayer of floating silicious slag, the tendency of which will be toprevent in a measure its mixture with the matte and to assist constantlyand continuously the escape of this top layer of slag through theoverflow-spout.

The foregoing explanation will make clear the fact that the movement ofunfused. ore, from the point of entrance at one end of the smeltingconverter to the point of escape at the overflow-spout, located at theother end of the vessel, will be rapid. Where the entering ore isdelivered into the vessel in a fine state or in highly silicious lumps,this movement may be rapid enough to carry such material and dischargeit in an unfused state through the overflow spout. If such materialescapes from the smelting converter unfused into the forehearth, thenthe recovery of its contained mineral values becomes impossible.

An object of our present invention therefore is to provide a bridge or acheck that will be practically in destructible and that will catch andhold any floating particles or lumps on the surface of the molten bath,before the same can escape through the overflowspout.

Another object of our invention is to accomplish this result without thepossibility of trapping the blast, for the reasons hereinbeforedescribed.

The violent action of the converting blast, as well as the very rapidmovement of molten slag and matte from the ore entrance to theoverflow-spout and thence into the forehearth, may be sufficient tocause floating particles or lumps of ore or silicate to pass under thebridge, as illustrated in the drawings. Should this occur, itconstitutes exactly the result that we wish to be produced; because inthis way each separate particle or lump will become submerged in themolten matte during its passage under the bridge, and this will have theeffect of immediately dissolving the then red hot ore and of compellingit to join the bath in molten form, in which form it becomes possible tore- This downward pressure on spout, and the slag-layer on top may thusbe forced to occupy a position above the level of the overflow-spout. Inthe case of the ordinary blast furnace equipped with a trapped overflow,the air pressure of the blast, obstructed by the unfused charge in thefurnace, exerts a top pressure upon the slag and this causes it to bedischarged through the overflow-spout with the matte. A floating layerof slag, however, is maintained constantly in a blast furnace, that maybe from eight to twelve inches in thickness owing to the depth of thetrap. No such assistance as the considerable top pressure hereindescribed, is available in our process of dissolving ores. For thisreason it is essential that our overflow-spout shall at all times befree and open, so that the upper floating layer of slag may at all timesfind a free and a ready exit. Any considerable thickness of floatingslag would have the effect of separating the floating ore from the bodyof low-grade corrosive matte, where alone it can be dissolved. In orderto explain this matter in clear terms, we quote the following table ofspecific gravities of materials ordinarily dealt with in smelting:

Pure silica, (SiO 2.60

Pure alumina, (A1 0 2.55

Pyrrhotite, (Fe S 4.50 to 4.65

Iron pyrites, (FeS 4.90

Copper pyn'tes, (OuFes 4.30

Copper mattes 4.60 to 5.1

Bornite, (Ou FeS 5.00

Ghalcocite, (C11 8) 5.5

Enargite, (Gu AsS 4.34 to 4.45 Slags 3.21 to 3.90

It will be noted that the specific gravity of silica or quartz and ofalumina or clay are such that these will float on slags. It will also benoted that the slags resulting from this smelting process will float oncopper mattes. The silicious portions of many ores as described aboveare almost as light as silica itself, and these will also float uponslags. Such silicious ores are the most difficult to dissolve or renderliquid by heat.

Our present invention relates especially to the recovery of anycontained mineral values in such highly silicious floating particles. Byplacing the bridge or dam as herein described at or near the surface ofthe molten bath, the travel of the floating particles can either bechecked until they have had time to dissolve, which result can beaccomplished in a few moments through the medium of the intense heat ofthe converting blast as well as the intense heat of the ore, at thisstage of the work when operating on low grade corrosive mattes, or theywill be compelled to pass under the bridge or dam and will thus besubmerged in the corrosive matte during their travel towards theoverflow-spout, which will also have the effect of dissolving them.

In the drawings, '7 illustrates the heavy walls of the convertingvessel, which may be made of solid metal blocks of such thickness thattheir bulk will bear such a relative proportion to the body of moltenbath that they will not be injured and that they will successfullyresist the heat and the corrosive action of the matte and thus bepractically indestructible, ordinary wear and tear excepted. It ispreferable that they should be supplemented with an interior refractorylining. The

use of these blocks however does not constitute part of our presentinvention, which. relates to other parts of the converting apparatus.

8 illustrates the converting twyers.

9 in Figs. 1, 2, 3, 4 and 5 illustrates the location and the design ofour preferred and alternate means for practicing our invention.

10 in Figs. '1, 2 and 3 illustrates removable blocks, so that thewater-cooled pipe or bridge 9 may be removed from the vessel, ifdesired, even when incrusted with congealed slag or matte. Our preferredform of apparatus, as illustrated in Figs. 1 and 2, shows this bridge orwater-cooled pipe so curved that the lower portion of it will skim thesurface of the molten bath while at its normal level at the center lineof the vessel. The advantage of this construction lies in the fact thatthe orifices through the converter wall are thus considerably higherthan the level of the molten bath, hence none of the matte or slag canescape around the blocks that fill these orifices, nor can the slag ormatte congeal injuriously upon the inside surfaces of the block and thusprevent or obstruct its removal when desired. Our alternateconstruction, which consists of a straight watercooled pipe or bridge,is illustrated in Figs. 4 and 5 and it is objectionable to the extentabove described, although with this apparatus successful skimming of thebath may be accomplished It is intended that the water or other coolingmedium shall enter at one side of the vessel preferably as shown at 1.1in Figs. 1 and 4, and that it shall escape as illustrated at 12 in thesame figures. In this way a continuous stream may beforced through thepipe, which will at all times maintain upon its exterior surface, byreason of this cooling action, a sufficient layer of con-' gealed matteand slag, to protect it against the heat and the corrosive slags andmattes that are inseparable from this work. In lieu of a continuousstream of water or other cooling medium passing entirely through thebridge or pipe 9, this pipe may be constituted of two separate pieces ofdifferent diameters, the one being located within the other. In suchevent, the cooling stream may enter through one of them and thereafterreturn at the point 13 in Fig. 1, and thus find its exit at or near thepoint of entrance.

It will be noted in Figs. 2 and 5 that the bridge is purposely located ashort distance in front of the orifice or overflow 14, the object beingto check the travel of any unfused ore while borne upon the surface ofthe molten matte sometime before its escape from the vessel. Should theparticles or the lumps be submerged in the molten matte, through theaction of the bridge and through the rapid motion of the molten bath inits travel towards the orifice 14' and thereafter in its exit from theoverflow-spout 15, sufficient travel is thus secured for,

such unfused particles or lumps while immersed in the molten matte andwhile heated red hot to accomplish their successful dissolving beforethey are dropped from the overflow-spout 15.

Very pure silica or a very pure lime constitute almost perfect oxids andfor this reason, they become practically infusible, excepting only inthe presence of such intense heat for instance as is produced in theelectric furnace. As soon however as even these perfect oxids come intocontact with iron, their affinity for this will quickly produce eithersilicate of iron or silicate of lime, and this fact renders themamenable to and capable of being melted by comparatively moderate heat,such for instance as that produced in the method of smelting hereindescribed.

Fig. 6 illustrates a possible method of accomplishing the successfulskimming and checking of the exit of unfused ore particles or lumps fromthe vessel. We do not recommend this method of accomplishing the result, for the reason that if carelessly used it might result eithertemporarily or continuously in trapping the blast and should this occur,it would be fatal to the successful practice of this art. The device asillustrated in Fig. 6 is intended to skim or to check the travel of anyfloating ore particles or lumps, by means of the overhanging projectionin the converter-wall shown at 16, the level of the molten bath being at17. It is intended, in. using this device, that the upper level of themolten bath shall never extend above the line 17 shown in the drawing.In other words, it is the intention that the travel of the ore shall bechecked at 16, or if it be carried forward, the projection 16 willautomatically cause its submersion in the molten bath and this will havethe effect of dissolving it. At the same time, the level of the moltenbath being at or about the line 17, the blast will still be permitted toescape past the projection 16 and the possible trapping of the blast orobstruction to the flow of the molten bath will be prevented.

Doubtless many modifications in the details of this means for preventingthe escape of un fused ore from smelting converters will suggestthemselves to those skilled in the art. Insofar as we know, this meansfor accomplishing the desired result is broadly new and as such weintend to claim it.

We claim 1. A smelting converter in which the smelting is effected bythe heat of oxidation of the ore charge having twyers, a constantly openoverflow at one end, and a bridge or bar rier placed near said openingand arranged to check floating particles of ore and submerge them in themolten bath in their movement towards said opening; substanrially asdescribed.

2. Means for preventing the escape of unfused ore from smeltingconverters which consists in the combination of a converter having adischarge opening, a barrier or bridge adapted to check floatingparticles or lumps, and an orifice through which the barrier or bridgeis inserted, said orifice being above the level of the barrier orbridge; substantially as described.

3. In a smelting converter having twycrs and in which the smelting iseffected solely by the heat of oxidation of the ore charge, and whichhas a constantly open discharge, means for preventing the escape ofunfused ore, consisting of a barrier or bridge loca ted near thedischarge opening and extending somewhat below the same so that theblast will not be trapped and floating unfused ore particles or lumpswill, in passing under the bridge or barrier, be submerged in the moltenmatte; substantially as de scribed.

4. Means for preventing the escape of unfused ore from smeltingconverters which consists in the combination of a converter havingtwyers, and a constantly open dischargeopening, a barrier or bridgeadapted to check floating particles or lumps, said barrier or bridgebeing in the converting chamber, and a toreheurth to which thedischargeopening lends; substantially as described.

Means for preventing the escape of unfused ore from smelting convertersin which the smelting is effected solely by the heat of oxidation of theore charge which consists in the combination of a converter of oblongform having 2.5 verier chamber behind and in transverse relation to thetwyers, an end discharge-opening, and a removable barrier or bridgeadapted to check floating particles or lumps said barrier or bridgebeing in the converting chamber; substantially as described.

6. Means for preventing the escape of untused ore from smeltingconverters in which the smelting is effected solely by the heat ofoxidation of the ore charge which con is in the combination of aconverter having twyers, a discharge-opening and a fluidcooled barrieror bridge adapted to check floating particles or lumps said barrier orbridge being in the converting chamber; substantially as de scribed.

T. Means for preventing the escape of unfused ore from smeltingconverters which consists in the combination of a converter having adischarge-opening, a barrier or bridge adapted to check floatingparticles or lumps. and an orifice through which the barrier or bridgeis inserted, said orifice being above the level of the barrier or bridgeand provided with a removable block; substantially as described.

S. The combination with a converter for smelting ores solely by the heatof their oxidation, said converter having twyers and a normally openoverflow or discharge opening, of means for preventing the discharge ofunfused ore at such opening consisting of a bridge or barrier in theconopening and arranged to check floating particles of ore and causethem to be submerged in their forward passage; substantially asdescribed 9. In a smelting converter having twyers, and a com stantlyopen overflow, means for preventing the escape of uni'used ore,comprising a bridge or barrier placed transversely of the said openingadjacent thereto, and extending somewhat below the same, and acting tocause the pieces 01' unfused ore which impinge against it to besubmerged in the molten matte in the converter; substantially asdescribed.

10. A smelting converter of the character described, having a singleconstantly open overflow opening at one end portion for both slag andmatte, and a barrier or bridge placed transversely of said opening inposition to catch and submerge floating pieces of ore; substantially asdescribed.

In testimony whereof, we have hereunto set our hands.

RALPH BAGGALEY. CHARLES M. ALLEN. EDWARD W. LINDQUIS'L.

Witnesses LYNN W. SMITH, AznLLn F. HOBART.

